I am trying to install Singular using your repository, but the version number is overrideen by Ubuntu's official version. The version provided by the repository is 4.0.3-1 and the Ubuntu version is 4.0.3+ds-1.

I suppose ds means Debian Science. The problem is I think Ubuntu's version is actually older and also the components are split up differently (e,g it has no singular-dev package)

I think this can be fixed if you just bumb the version number in your repository. Thanks.